Drill rod having internally projecting portions

ABSTRACT

A threaded drill string component having a hollow elongate body with a box end portion, an opposing pin end portion and a cylindrical mid-body portion that extends longitudinally between the respective box and pin end portions and has a variable wall diameter. The mid-body inner wall of the mid-body portion has at least one projecting portion or upset that is spaced from both the box and pin end portions and extends inwardly toward a central longitudinal axis of the hollow body and a plurality of troughs defined in the mid-body inner wall of the mid-body portion.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a U.S. National Phase Application of InternationalApplication No. PCT/US2015/040929, filed Jul. 17, 2015, which claimspriority to and the benefit of U.S. Provisional Application No.62/026,399, filed Jul. 18, 2014. Both applications are hereinincorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

Field

Implementations of the present invention relate generally to componentsand systems for drilling. In particular, implementations of the presentinvention relate to drill rods having at least one of reduced overallweight, increased strength, or resistance to jamming and/or wedging.

Relevant Technology

Drilling core samples (or core sampling) allows observation ofsubterranean formations within the earth at various depths for manydifferent purposes. For example, by drilling a core sample and testingthe retrieved core, scientists can determine what materials, such aspetroleum, precious metals, and other desirable materials, are presentor are likely to be present at a desired depth. In some cases, coresampling can be used to give a geological timeline of materials andevents. As such, core sampling may be used to determine the desirabilityof further exploration in a particular area.

In drilling relatively deep wells, such as those which reach a depth ofseveral hundred to several thousand feet deep, a plurality of drill rodsections, which typically have conventional lengths, are coupledend-to-end together in series to form a drill string. The connectionbetween these drill rod sections is made by fasteners, usually threadedfasteners. One limitation on the drilling of relatively deep wells isthe drill string weight, which of course becomes greater and greater asthe well depth is increased. Historically, drill rod sections have beenmade of steel with a substantially constant internal diameter; but withthe deeper wells now being drilled, the heavier drill strings can imposefatiguing loads on the component drill rod sections and on the equipmentused to rotate and raise and lower the drill string.

In order to properly explore an area or even a single site, many coresamples may be needed at varying depths. In some cases, core samples maybe retrieved from thousands of feet below ground level. In such cases,retrieving a core sample may require the time consuming and costlyprocess of removing the entire drill string (or tripping the drillstring out) from the borehole. In other cases, a faster wireline coredrilling system may include a core retrieval assembly that travels (ortrips in and out of) the drill string by using a wireline cable andhoist.

In operation, the time to trip the core sample tube in and out of thedrill string often remains a time-consuming portion of the drillingprocess. The slow tripping rate of the core retrieval assembly of someconventional wireline systems in a drill string formed from conventionaldrill rod may be caused by several factors. For example, the coreretrieval assembly of some wireline systems may include a spring-loadedlatching mechanism. Often the latches of such a mechanism may dragagainst the interior surface of the drill string and, thereby, slow thetripping of the core sample tube in the drill string. Additionally,because drilling fluid and/or ground fluid may be present inside thedrill string, the movement of many conventional core retrievalassemblies within the drill string may create a hydraulic pressure thatlimits the rate at which the core sample tube may be tripped in and outof the borehole. The increased internal diameter of the drill rod of thepresent invention helps to reduce the impact of these factors andprovides an increased efficiency in operation.

Accordingly, a need exists for improved drill rods that address one ormore of the issues described above. For example, there is a need fordrill rods that have reduced overall weight while maintaining orminimizing loss of stiffness in bending and twisting and loss of supportagainst the bending and twisting of a drill string passing therethrough,as well as using available material effectively to increase drillingload capacity.

SUMMARY

It is to be understood that this summary is not an extensive overview ofthe disclosure. This summary is exemplary and not restrictive, and it isnot intended to identify key or critical elements of the disclosure ordelineate the scope thereof. The sole purpose of this summary is toexplain and exemplify certain concepts of the disclosure as anintroduction to the following complete and extensive detaileddescription.

One or more implementations of the present invention overcome one ormore of the foregoing or other problems in the art with drillingcomponents, tools, and systems that provide for effective and efficientdrilling. In one aspect, one or more implementations of the presentinvention comprise a threaded drill string component that resistsmid-body twisting.

In one aspect the threaded drill string component comprises a hollowelongate body having a box end portion and an opposing pin end portion.Each of the respective box and pin end portions have an end portioninner wall having a first inner diameter. In a further aspect, thehollow body further comprises a cylindrical mid-body portion thatextends longitudinally between the respective box and pin end portions.The cylindrical mid-body portion has a mid-body inner wall having avariable wall diameter and a mid-body outer wall having a substantiallyconstant outer diameter.

In another aspect, the mid-body inner wall of the mid-body portion canhave at least one projecting portion having at least one male projectionor upset that is spaced from both the box and pin end portions andextends inwardly toward a central longitudinal axis of the hollow bodyand a plurality of troughs defined in the mid-body inner wall of themid-body portion. In one aspect, it is contemplated that the at leastone male projection of each projecting portion has a male projectioninner wall face that can have a second inner diameter, which can beequal to or greater than the first inner diameter.

In another exemplary non-limiting aspect, a first trough can extend froma distal end of the box end portion to a proximal end of the at leastone male projection of a projecting portion and a second trough canextend from a distal end of the at least one male projection of theprojecting portion to a proximal end of the pin end portion. In thisaspect, each trough can comprise a substantially cylindrical portionhaving a first trough diameter that is greater than the respective firstand second inner diameters.

Additional features and advantages of exemplary implementations of theinvention will be set forth in the description which follows, and inpart will be obvious from the description, or may be learned by thepractice of such exemplary implementations. The features and advantagesof such implementations may be realized and obtained by means of theinstruments and combinations particularly pointed out in the appendedclaims. These and other features will become more fully apparent fromthe following description and appended claims, or may be learned by thepractice of such exemplary implementations as set forth hereinafter.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments and together with thedescription, serve to explain the principles of the methods and systems.

FIG. 1 illustrates a drilling system having a plurality of connecteddrill rods in a drill string in accordance with one or moreimplementations of the present invention;

FIG. 2 is a cross-sectional view of an exemplary drill string componentor drill rod having a single projecting portion (i.e., male projection)as disclosed herein;

FIG. 3 is a cross-sectional view of an exemplary drill string componentor drill rod as disclosed herein; and

FIG. 4 is a cross-sectional view of an exemplary drill string componentor drill rod having a plurality of axially spaced projecting portions(i.e., male projections) as disclosed herein.

DETAILED DESCRIPTION

Before the present methods and systems are disclosed and described, itis to be understood that the methods and systems are not limited tospecific synthetic methods, specific components, or to particularcompositions. It is also to be understood that the terminology usedherein is for the purpose of describing particular embodiments only andis not intended to be limiting.

As used in the specification and the appended claims, the singular forms“a,” “an” and “the” include plural referents unless the context clearlydictates otherwise. Ranges may be expressed herein as from “about” oneparticular value, and/or to “about” another particular value. When sucha range is expressed, another embodiment includes from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. It will be further understood that the endpoints of each ofthe ranges are significant both in relation to the other endpoint, andindependently of the other endpoint.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where said event or circumstance occurs and instances where itdoes not.

Throughout the description and claims of this specification, the word“comprise” and variations of the word, such as “comprising” and“comprises,” means “including but not limited to,” and is not intendedto exclude, for example, other additives, components, integers or steps.“Exemplary” means “an example of” and is not intended to convey anindication of a preferred or ideal embodiment. “Such as” is not used ina restrictive sense, but for explanatory purposes.

Disclosed are components that can be used to perform the disclosedmethods and systems. It is understood that when combinations, subsets,interactions, groups, etc. of these components are disclosed that whilespecific reference of each various individual and collectivecombinations and permutation of these may not be explicitly disclosed,each is specifically contemplated and described herein, for all methodsand systems. This applies to all aspects of this application including,but not limited to, steps in disclosed methods. Thus, if there are avariety of additional steps that can be performed it is understood thateach of these additional steps can be performed with any specificembodiment or combination of embodiments of the disclosed methods.

The present methods and systems may be understood more readily byreference to the following detailed description of preferred embodimentsand the Examples included therein and to the Figures and their previousand following description. Reference will now be made to the drawings todescribe various aspects of one or more implementations of theinvention. It is to be understood that the drawings are diagrammatic andschematic representations of one or more implementations, and are notlimiting of the present disclosure. Moreover, while various drawings areprovided at a scale that is considered functional for one or moreimplementations, the drawings are not necessarily drawn to scale for allcontemplated implementations. The drawings thus represent an exemplaryscale, but no inference should be drawn from the drawings as to anyrequired scale.

In the following description, numerous specific details are set forth inorder to provide a thorough understanding of the present disclosure. Itwill be obvious, however, to one skilled in the art that the presentdisclosure may be practiced without these specific details. In otherinstances, well-known aspects of drill string technology have not beendescribed in particular detail in order to avoid unnecessarily obscuringaspects of the disclosed implementations.

In certain aspects, implementations of the present disclosure providefor improved drill string components that preserve load, torsional, andimpact capacity while minimizing the weight of the drill stringcomponent. Additionally, it is contemplated that reducing the weight ofeach individual drill rod can allow for the subsequent increase in thecapacity of a drilling system to manage more drill or coring rods,thereby increasing the overall drilling system depth capacity. Forexample, it is contemplated that a drill rated for 2500 m can manage a3250 m drill string when using the drill rods disclosed. Further, it iscontemplated that increasing the internal diameter of the drilling rodcan allow the drilling system to be more efficient in tripping a coresample tube in and out of the drill string.

In other optional aspects, implementations of the present disclosuremaintain a continuous metal exterior surface and, thus, avoid anyabrasive wear of a composite lining positioned therein the troughs ofthe drill string components disclosed herein.

In other aspects, implementations of the present disclosure provide formore accurate drilling results by increasing the stiffness of the drillstring components and, thus, the drill string. In light of the presentdisclosure, one skilled in the art will appreciate that the increasedstiffness associated with the male projections provided in the drillstring component can result in an increased stiffness of the drillstring component. This increased stiffness can reduce the deflection ofthe drill string and, correspondingly, the drilled hole, therebyproviding more accurate drilling results such as, for example andwithout limitation, improved blasting efficiency when drilling blastholes, improved targeting in mineral exploration, and the like.

Implementations of the present invention are directed toward drillingcomponents, tools, and systems that provide for a threaded drill stringcomponent that resists mid-body twisting while minimizing the weight ofthe drill string component. Turning now to FIGS. 1-4, implementations ofexemplary threaded drill string components are illustrated.

In one aspect the threaded drill string component or drill rod 100comprises a hollow elongate body 10 having a box end portion 20, anopposing pin end portion 30 and a cylindrical mid-body portion 40 thatextends longitudinally between the respective box and pin end portions.A central longitudinal axis LA extends through the hollow body 10between the respective box and pin end portions 20, 30. Each of therespective box and pin end portions 20, 30 have an end portion innerwall 22, 32 having a first inner diameter D1. In one aspect, the endportion inner wall 22,32 can have a substantially cylindrical shape thatis positioned uniformly about the central longitudinal axis. In afurther aspect, the cylindrical mid-body portion 40 has a mid-body innerwall 42 having a variable wall diameter and a mid-body outer wall 43having a substantially constant outer diameter. Although describedherein as having the same inner diameter D1, it is contemplated that theinner walls 22, 32 of the box and pin end portions 20, 30 can optionallyhave different inner diameters.

In another aspect, the mid-body inner wall 42 of the mid-body portioncan have at least one projecting portion having at least one maleprojection 44 or upset that is spaced from both the box and pin endportions 20, 30 and extends inwardly toward the central longitudinalaxis LA of the hollow body 10 and a plurality of troughs 60 defined inthe mid-body inner wall 42 of the mid-body portion 40. In one aspect, itis contemplated that each projection of the at least one male projection44 has a male projection inner wall face 46 that can have a second innerdiameter D2 that can be equal to or greater than the first innerdiameter D1. In one aspect, the male projection inner wall face 46 canhave a substantially cylindrical shape that is positioned uniformlyabout the central longitudinal axis LA. In this aspect, each maleprojection 44 can have, in a perpendicular plane bisecting the centrallongitudinal axis LA, a substantially torodial shape.

In another exemplary aspect, a first trough 60′ of the plurality oftroughs 60 can extend from a distal end 24 of the box end portion 20 toa proximal end 50 of the at least one male projection 44 and a secondtrough 60″ of the plurality of troughs 60 can extend from a distal end52 of the at least one male projection to a proximal end 34 of the pinend portion 30. In this aspect, each trough 60 can comprise asubstantially cylindrical portion 62 having a first trough diameter thatis greater than the respective first and second inner diameters. Eachtrough can also have a first frustoconical portion 64 that is slopedoutwardly from the central longitudinal axis LA and extends between therespective distal end 24 of the box end portion 20 and proximal end 34of the pin end portion 30 to the substantially cylindrical portion 62and has a variable inner diameter that is greater than the first innerwall diameter D1. In an optional aspect, not shown, at least a portionof the substantially cylindrical portion of each trough 60 can furthercomprise a plurality of longitudinally extending ridges that extendinwardly toward the central longitudinal axis LA.

In a further aspect, a portion of each trough 60 adjacent to the atleast one male projection 44 can comprise a second frustoconical portion66 that is sloped inwardly from the central longitudinal axis LA andextends between the substantially cylindrical portion 62 of the mid-bodyportion and an edge 47 of the male projection inner wall face 46. It iscontemplated that the first and second frustroconical portions 64, 66can have any desired longitudinal cross sectional shape. In one example,and not meant to be limiting, at least a portion of each secondfrustoconical portion 66 can be linear in longitudinal cross-section andcan be positioned at an acute angle β with respect to a perpendicularplane bisecting the central longitudinal axis LA. In one aspect, theacute angle β can be between about 0.01 to about 10 degrees; preferablyless than about 8 degrees; and, more preferred, less than about 6degrees. In exemplary aspects, the acute angle β can range from about0.5 to about 8 degrees, from about 0.5 to about 6 degrees, from about0.5 to about 5 degrees, from about 1 to about 7 degrees, from about 1 toabout 6 degrees, from about 1 degrees to about 5 degrees, or from about2 degrees to about 6 degrees.

In one aspect, it is contemplated that at least a portion of each secondfrustoconical portion 66 can be curvilinear in longitudinalcross-section. Similarly, it is contemplated that at least a portion ofeach first frustoconical portion 64 can be linear and/or curvilinear inlongitudinal cross-section. In another aspect, at least a portion ofeach first frustoconical portion 64 can have a quarter sine wave shapein longitudinal cross-section with an amplitude equal to one-half of thefirst trough diameter.

In another aspect, at each first frustoconical portion 64, the innerdiameter of the hollow body 10 can transition from the second innerdiameter D2 of the male projection inner wall face 46 to the firsttrough diameter along a first longitudinal transition length L1.Similarly, at each second frustoconical portion 66, the inner diameterof the hollow body 10 can transition from the first inner diameter D1 ofthe respective box and pin end portions 20, 30 to the first troughdiameter along a second longitudinal transition length L2. The total ofthe respective first and second transition lengths L1, L2 is less thanabout 15%, preferably less than about 12.5% and, more preferred, lessthan about 10% of the overall length of the drill rod.

In various exemplary aspects, the elongate length of the plurality oftroughs can comprise greater than 60% of the elongate length of themid-body portion; preferably greater than 70% of the elongate length ofthe mid-body portion, and more preferred, greater than 80% of theelongate length of the mid-body portion.

In a further aspect, it is contemplated that the transition from thesecond frustoconical portion 66 to the male projection inner wall face46 can be chamfered. Similarly, it is contemplated that the transitionfrom the second frustoconical portion 66 to the adjoining cylindricalportion of the mid-body portion 40 of the trough 60 can be chamfered.

In another aspect, and as shown in FIGS. 2 and 3, it is contemplatedthat the at least one male projection 44 of each projecting portion cancomprise a single male projection, which can optionally extendcircumferentially about the central longitudinal axis LA. Alternatively,it is contemplated that the at least one male projection 44 of eachprojecting portion can comprise a plurality of circumferentially spacedmale projections. Optionally, in exemplary aspects, the at least oneprojecting portion can comprise a single projecting portion (i.e., asingle axial location with at least one male projection) that ispositioned at a desired axial location in the mid-body portion. As onewill appreciate from the above disclosure, it is contemplated that therespective end portion inner walls 22, 32 of the box and pin endportions 20, 30 can effectively act as an additional internal maleprojection or upset 44′ that is located at the respective outer endportions of the hollow body 10 of the drill rod 100.

In one aspect, the axial spacing between sequential projecting portions(e.g., sequential axial locations with at least one male projection 44)and/or the axial spacing between the pin and box end portions 20, 30,44′ and a sequential projecting portion (e.g., at least one maleprojection 44), which effectively corresponds to the spacing between theinternal upsets in the drill string component, can reflect a selectedseparation distance. For example and without limitation, when the drillstring components disclosed herein are used as casings for other drillstring components to be passed therethough, the selected separationdistance (e.g., the spacing between sequential male projections 44and/or the spacing between a male projection and the pin and box endportions 20, 30, 44′) can be made relative to and as a percentage of theelongate length of the individual respective drill string componentsbeing passed therethrough. For example, if a drill string componentbeing passed through the drill rod is 10 feet in length, then theselected separation distance would be less than 100% of the elongatelength of the drill string component passing through the drill rod. Inthis aspect, it is contemplated that the selected separation distancecan correspond to a distance that is less than about 90%, less thanabout 80%, less than about 70%, less than about 60%, less than about50%, less than about 40%, or less than about 30% of the elongate lengthof the individual drill string components that are passed therethroughthe hollow body 10 of the drill rod 100 (or other drill stringcomponent). In exemplary aspects, it is contemplated that the selectedseparation distance can range from about 1 foot to about 6 feet and morepreferably, from about 2 feet to about 5 feet and, most preferably, fromabout 3 feet to about 5 feet. In further exemplary aspects, it iscontemplated that the selected separation distance can be less thanabout 5 feet.

In one example, and as shown in FIG. 4, a first projecting portion(e.g., a first axial location of at least one male projection 44) can bepositioned substantially in the center of the mid-body portion 40.Optionally, when the at least one projecting portion comprises aplurality of projecting portions (e.g., a plurality of axially spacedlocations of at least one male projection 44), the plurality ofprojecting portions can be spaced longitudinally along the mid-bodyportion 40. It is contemplated that the spacing can be substantiallyuniform or it can be varied as desired. In exemplary aspects, and asshown in FIG. 4, the plurality of projecting portions can comprise apair of spaced projecting portions that are equidistantly spacedlongitudinally along the mid-body portion from each other and from therespective internal male projection or upset 44′ defined by therespective end portion inner walls 22, 32 of the box and pin endportions 20,30. In these aspects, each projecting portion can compriseat least one male projection 44 as disclosed herein. In these aspects,and as one skilled in the art will appreciate, the plurality of troughs66 can comprise at least one trough that extends between any two spacedprojecting portions (e.g., any two sequential axial locations of atleast one male projection 44), to include the internal male projectionor upset 44′ defined by the respective end portion inner walls 22, 32 ofthe box and pin end portions 20, 30.

In other aspects, the drill string component 100 can have improvedresponse under dynamic loading conditions over conventional drill rods.The typical dynamic response of steel drill strings under compressionand high r.p.m. indicate that the torque impulse loads from the drillbit create torsion and bending load waves that can rapidly travel up andreflect back down the drill string. This dynamic response can magnifythe impulse load by a factor of about 2 to about 3, and suchmagnification can exceed the elastic limit of the conventional drillrod. One skilled in the art will appreciate that exceeding the elasticlimit of the conventional drill rod under these loading conditions canlead to permanent twisting and bending of the drill string which, inturn, can prevent productive drilling or even seizing of the drillstring in the hole. However, these impulse loads are typicallyinsufficient to overload the drill rod joints. Here, using the drillstring component 100 described herein having a male projection(s) 44positioned in the midbody portion 40 can allow for an increasedresistance to bending by the component. Additionally, it is contemplatedthat, for applications in which the drill string component is being usedas a casing for other drill string components to be passed therethough,spacing the distances between the projecting portions (e.g., axiallocations of at least one male projection 44) and/or the pin and box endportions 20,30, 44′ (i.e., spacing the distances between the internalupsets in the drill string component) to the selected separationdistances disclosed herein can help to prevent undesired twisting ofboth the drill string component being used as a casing and the otherdrill string components being passed therethough.

In a further aspect, the substantially cylindrical portion 62 of themid-body inner wall 42 and the overlying mid-body outer wall 62 can forma portion of a mid-body cylindrical wall having a substantially constantthickness that can have, in a plane bisecting the central longitudinalaxis LA, a cross-sectional wall thickness of between about 1 percent andabout 10 percent of the outer diameter of the mid-body outer wall.Further, it is contemplated that the cross-sectional wall thickness ofeach mid-body cylindrical wall can range between about 60 to about 80percent of the cross sectional wall thickness of the at least projectingportion (e.g., each axial location of at least one male projection 44).

In an exemplary aspect, and not to be limiting, it is contemplated thatfor a nominal cross-sectional wall thickness of each mid-bodycylindrical wall of about 0.155 inches, the respective thicknesses ofthe box and pin end portions 20, 30 can range from about 0.188 inches toabout 0.25.

In one aspect, the inner diameter of each trough 60 proximate the atleast one male projection, in any cross-sectional plane transverse tothe central longitudinal axis LA, can be less than second inner diameterD2.

With continuing reference to the figures, which illustrate the box andpin end portions 20, 30 of the hollow body 10 of the drill stringcomponent or drill rod 100, it is contemplated that the box end portioncan typically be located at the bit end of the drill rod. The box endportion 20 of the drill rod 100 can be configured to be coupled withadditional drill rods or other drill components, such as a drill bit. Inparticular, in one example, the pin end portion 30 can be configured asand/or comprise a male-type interface that is configured to be coupledto a box end portion of a female-type interface in an associated dripcomponent. The pin end portion 30 can also be configured to includeexternal threading to facilitate coupling or communication with internalthreading of an associated drill rod or other drill components. The boxend portion 20 can also comprise any other external shaping thatfacilitates coupling with additional drill rods or other drillcomponents. For example and without limitation, the box end portion 20can be star-shaped, gear-shaped, hexagonally-shaped, and the like.

In exemplary aspects, the box end portion 20 can have a female threaddefined therein and the pin end portion 30 can have a male threadpositioned thereon that is configured to be complementarily receivedtherein the female thread. Exemplary thread shapes include conventionalthread shapes; Q and RQ thread shapes practiced by Applicant, andthreads disclosed in Applicant's co-pending U.S. patent application Ser.Nos. 13/354,189, 13/717,885, and 14/026,611, which are incorporated byreference herein in their entirety.

In one aspect, the drill string component 100 can be manufactured fromsteel material. In one example, and not meant to be limiting, the drillstring component 100 can be manufactured from a chromium molybdenumalloy steel grade such as AISI.SAE 4130 or modified versions thereof. Inis contemplated that the drill string component 100 can beconventionally cold drawn and annealed to desired shape and materialperformance characteristics. It is contemplated that the as-drawnhardness of the cold drawn annealed tubing can be at least about 95 onthe Rockwell Hardness B scale (“HRB”), which is typically between about17 to 20 on the Rockwell Hardness C scale (“HRC”).

In another aspect, it is contemplated that at least portions of therespective pin and box end portions 20, 30 and the at least one maleprojection 44 can be hardened to a desired surface hardness byconventional means, such as, for example and without limitation, bycarburizing at least the end portion inner wall 22, 32 and/or maleprojection inner wall face 46 or by induction surface hardening of atleast the end portion inner wall 22, 32 and/or male projection innerwall face 46 (by low frequency induction heating means followedimmediately by cold quenching). In particular, in one or moreimplementations, the hardened portions of the at least the end portioninner wall 22, 32 and/or male projection inner wall face 46 can have ahardness between about 25 HRC to about 55 HRC. Optionally, the hardenedportions can have a hardness between about 20 HRC and about 30 HRC orbetween about 30 HRC and about 40 HRC. In still further options, thehardened portions can have a hardness between about 35 HRC and about 45HRC. One will appreciate that the hardened portions can be treated toinclude a hardness in a range between any of the above recited numbers.It is also contemplated that, optionally, the entirety of the portion ofthe respective pin and box end portions 20, 30 and/or the at least onemale projection 44 can be heat treated to the desired hardness or onlydesired portions, such as, exemplarily, the inner faces, of therespective pin and box end portions and/or the at least one maleprojection can be heat treated to the desired hardness.

In another exemplary aspect, it is contemplated that the disclosed drillrods and other drill string components can have characteristics as setforth in the following table. The first column of the chart gives thecharacteristics of conventional drill rods, whereas the second and thirdcolumns give exemplary characteristics of drill rods having of drillstring component of the present disclosure:

Single Male Two Male Projecting Projecting Conventional Portion PortionsDrill Rod FIG. 2 FIGS. 3, 4 Outer Diameter (inches) 3.5 3.5 3.5 InnerDiameter 3.0625 3.0625 3.0625 (minimum, inches) Inner Diameter (trough,inches) — 3.188 3.188 End Length (inches) — 8 8 Transition Length(inches) — 2.4 1.75 Calculated Angle β (degrees) — 1.50 2.05 OverallLength (inches) 122 122 122 Number of Mid-body Projecting 0 1 2 Portions(with at least one male projection) Male Projection Length (inches) — 32.5 Total Transition Length (inches) — 9.6 10.5 Total Trough Length(inches) — 93.4 90.5 Total Weight 78.68 lbs. 61.39 lbs. 61.82 lbs. TotalWeight Reduction — 22% 21.4%Exemplary Aspects

In various exemplary aspects, disclosed herein is a threaded drillstring component that resists mid-body twisting, comprising: a hollowbody having a box end portion, an opposing pin end portion, and acentral longitudinal axis extending through the hollow body, whereineach of the box end portion and the opposing pin end portion have an endportion inner wall having a first inner diameter; the hollow bodyfurther comprising a cylindrical mid-body portion that extendslongitudinally between the respective box and pin end portions and has amid-body inner wall having a variable wall diameter and a mid-body outerwall having a substantially constant outer diameter, the mid-bodyportion further comprising: at least one projecting portion spaced fromboth the box and pin end portions and extending inwardly toward thecentral longitudinal axis, wherein each projecting portion comprises atleast one male projection having a male projection inner wall facehaving an second inner diameter, wherein the second inner diameter isequal to or greater than the first inner diameter; and a plurality oftroughs defined in the mid-body inner wall of the mid-body portion,wherein a first trough of the plurality of troughs extends from a distalend of the box end portion to a proximal end of the at least oneprojecting portion and wherein a second trough of the plurality oftroughs extends from a distal end of the projecting portion to aproximal end of the pin end portion, wherein each trough comprises asubstantially cylindrical portion having a first trough diameter that isgreater than the respective first and second inner diameters and a firstfrustoconical portion that is sloped outwardly from the centrallongitudinal axis and extends between the respective distal end of thebox end portion and the proximal end of the pin end portion to thesubstantially cylindrical portion and has a variable inner diameter thatis greater than the first inner wall diameter, wherein the substantiallycylindrical portion of the mid-body inner wall and the overlyingmid-body outer wall form a portion of a mid-body cylindrical wall havinga substantially constant thickness and wherein, in a plane bisecting thecentral longitudinal axis, the cross-sectional thickness of eachmid-body cylindrical wall has a wall thickness of between about 1percent and about 10 percent of the outer diameter of the mid-body outerwall.

In another exemplary aspect, the end portion inner wall has asubstantially cylindrical shape that is positioned uniformly about thecentral longitudinal axis.

In another exemplary aspect, the male projection inner wall face has asubstantially cylindrical shape that is positioned uniformly about thecentral longitudinal axis.

In another exemplary aspect, the inner diameter of each trough proximatethe at least one male projection of each projecting portion, in anycross-sectional plane transverse to the central longitudinal axis, isless than the second inner diameter.

In another exemplary aspect, a portion of each trough adjacent to the atleast one male projection of each projecting portion, comprises a secondfrustoconical portion that is sloped inwardly from the centrallongitudinal axis and extends between the substantially cylindricalportion of the mid-body portion and an edge of the male projection innerwall face. In another exemplary aspect, at least a portion of eachsecond frustoconical portion is linear in longitudinal cross-section andis positioned at an acute angle β with respect to the centrallongitudinal axis. Optionally, in another exemplary aspect, the acuteangle β is less than about 6 degrees. Optionally, in another exemplaryaspect, a transition from the second frustoconical portion to the maleprojection inner wall face is chamfered. Optionally, in anotherexemplary aspect, a transition from the second frustoconical portion tothe adjoining cylindrical portion of the mid-body portion of the troughis chamfered. Optionally, in another exemplary aspect, at least aportion of each second frustoconical portion is curvilinear inlongitudinal cross-section.

In another exemplary aspect, a transition from each first frustoconicalportion of each trough to the adjoining respective distal end of the boxend portion and proximal end of the pin end portion is chamfered. Inanother exemplary aspect, the pin end portion has a male threadpositioned thereon, the male thread configured to be complementarilyreceived therein the female thread.

In another exemplary aspect, the box end portion has a female threaddefined therein.

In another exemplary aspect, the at least one projecting portioncomprises a single projecting portion positioned substantially in acenter of the mid-body portion. Optionally, in another exemplary aspect,the male projections of the single projecting portion are longitudinallyspaced from the box and pin end portions by a separation distance thatis less than about five feet.

In another exemplary aspect, the at least one projecting portioncomprises a plurality of projecting portions that are spacedlongitudinally along the mid-body portion. Optionally, in anotherexemplary aspect, the plurality of projecting portions are equidistantlyspaced longitudinally along the mid-body portion. Optionally, in anotherexemplary aspect, the plurality of troughs comprises at least one troughthat extends between any two spaced projecting portions. Optionally, inanother exemplary aspect, the male projections of sequential projectingportions are longitudinally spaced from one another by a separationdistance that is less than about five feet.

In another exemplary aspect, at least a portion of each firstfrustoconical portion is linear in longitudinal cross-section.

In another exemplary aspect, at least a portion of each firstfrustoconical portion is curvilinear in longitudinal cross-section.Optionally, in another exemplary aspect, at least a portion of eachfirst frustoconical portion has a quarter sine wave shape inlongitudinal cross-section with an amplitude equal to one-half of thefirst trough diameter. Optionally, in another exemplary aspect, eachfirst frustoconical portion has a quarter sine wave shape inlongitudinal cross-section with an amplitude equal to one-half of thefirst trough diameter.

In another exemplary aspect, at each second frustoconical portion, theinner diameter of the hollow body transitions from the first innerdiameter of the respective box and pin end portions to the first troughdiameter along a second longitudinal transition length, and wherein, ateach first frustoconical portion, the inner diameter of the hollow bodytransitions from the second inner diameter of the male projection innerwall face to the first trough diameter along a second longitudinaltransition length, and wherein the total of the respective first andsecond transition lengths is less than about 10% of the overall lengthof the drill string component.

In another exemplary aspect, the drill string component comprises adrill rod.

In another exemplary aspect, at least a portion of the substantiallycylindrical portion of each trough further comprises a plurality oflongitudinally extending ridges that extend inwardly toward the centrallongitudinal axis.

In another exemplary aspect, the plurality of troughs comprise greaterthan 60% of the elongate length of the mid-body portion.

In another exemplary aspect, the plurality of troughs comprise greaterthan 70% of the elongate length of the mid-body portion.

In another exemplary aspect, the plurality of troughs comprise greaterthan 80% of the elongate length of the mid-body portion.

In another exemplary aspect, at least a portion of the respective pinand box end portions and the at least one male projection can behardened to a desired surface hardness, and wherein the desired surfacehardness is between about 35 HRC and about 45 HRC.

The present invention can thus be embodied in other specific formswithout departing from its spirit or essential characteristics. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A threaded drill string component that resistsmid-body twisting, comprising: a hollow body having a box end portion,an opposing pin end portion, and a central longitudinal axis extendingthrough the hollow body, wherein each of the box end portion and theopposing pin end portion have an end portion inner wall having a firstinner diameter; the hollow body further comprising a cylindricalmid-body portion that extends longitudinally between the respective boxand pin end portions and has a mid-body inner wall having a variablewall diameter and a mid-body outer wall having a substantially constantouter diameter, the mid-body portion further comprising: at least oneprojecting portion spaced from both the box and pin end portions andextending inwardly toward the central longitudinal axis, wherein eachprojecting portion comprises at least one male projection having a maleprojection inner wall face having a second inner diameter, wherein thesecond inner diameter is equal to or greater than the first innerdiameter; and a plurality of troughs defined in the mid-body inner wallof the mid-body portion, wherein a first trough of the plurality oftroughs extends from a distal end of the box end portion to a proximalend of the at least one projecting portion and wherein a second troughof the plurality of troughs extends from a distal end of the projectingportion to a proximal end of the pin end portion, wherein each troughcomprises a substantially cylindrical portion having a first troughdiameter that is greater than the respective first and second innerdiameters and a first frustoconical portion that is sloped outwardlyfrom the central longitudinal axis and extends between the respectivedistal end of the box end portion and the proximal end of the pin endportion to the substantially cylindrical portion and has a variableinner diameter that is greater than the first inner diameter, whereinthe substantially cylindrical portion of the mid-body inner wall and theoverlying mid-body outer wall form a portion of a mid-body cylindricalwall having a substantially constant thickness and wherein, in a planebisecting the central longitudinal axis, a cross-sectional thickness ofeach mid-body cylindrical wall has a wall thickness of between about 1percent and about 10 percent of the outer diameter of the mid-body outerwall.
 2. The drill string component as recited in claim 1, wherein theend portion inner wall has a substantially cylindrical shape that ispositioned uniformly about the central longitudinal axis.
 3. The drillstring component as recited in claim 1, wherein the male projectioninner wall face has a substantially cylindrical shape that is positioneduniformly about the central longitudinal axis.
 4. The drill stringcomponent as recited in claim 1, wherein the inner diameter of eachtrough proximal to the at least one male projection of each projectingportion, in any cross-sectional plane transverse to the centrallongitudinal axis, is less than the second inner diameter.
 5. The drillstring component as recited in claim 1, wherein a portion of each troughadjacent to the at least one male projection of each projecting portion,comprises a second frustoconical portion that is sloped inwardly fromthe central longitudinal axis and extends between the substantiallycylindrical portion of the mid-body portion and an edge of the maleprojection inner wall face.
 6. The drill string component as recited inclaim 5, wherein at least a portion of each second frustoconical portionis linear in longitudinal cross-section and is positioned at an acuteangle β with respect to the central longitudinal axis.
 7. The drillstring component as recited in claim 6, wherein the acute angle β isless than about 6 degrees.
 8. The drill stung component as recited inclaim 6, wherein a transition from the second frustoconical portion tothe male projection inner wall face is chamfered.
 9. The drill stringcomponent as recited in claim 8, wherein a transition from the secondfrustoconical portion to the adjoining cylindrical portion of themid-body portion of the trough is chamfered.
 10. The drill stringcomponent as recited in claim 1, wherein a transition from each firstfrustoconical portion of each trough to the adjoining respective distalend of the box end portion and proximal end of the pin end portion ischamfered.
 11. The drill string component as recited in claim 10,wherein the pin end portion has a male thread positioned thereon, andwherein the box end portion has a female thread defined therein.
 12. Thedrill string component as recited in claim 1, wherein the at least oneprojecting portion comprises a single projecting portion positionedsubstantially in a center of the mid-body portion.
 13. The drill stringcomponent as recited in claim 1, wherein the at least one projectingportion comprises a plurality of projecting portions that are spacedlongitudinally along the mid-body portion.
 14. The drill stringcomponent as recited in claim 13, wherein the plurality of troughscomprises at least one trough that extends between any two spacedprojecting portions.
 15. The drill string component as recited in claim5, wherein at least a portion of each second frustoconical portion iscurvilinear in longitudinal cross-section.
 16. The drill stringcomponent as recited in claim 1, wherein at least a portion of eachfirst frustoconical portion is linear in longitudinal cross-section. 17.The drill string component as recited in claim 1, wherein at least aportion of each first frustoconical portion is curvilinear inlongitudinal cross-section.
 18. The drill string component as recited inclaim 5, wherein, at each second frustoconical portion, the innerdiameter of the hollow body transitions from the first inner diameter ofthe respective box and pin end portions to the first trough diameteralong a second longitudinal transition length, and wherein, at eachfirst frustoconical portion, the inner diameter of the hollow bodytransitions from the second inner diameter of the male projection innerwall face to the first trough diameter along a first longitudinaltransition length, and wherein the total of the respective first andsecond longitudinal transition lengths is less than about 10% of theoverall length of the drill string component.
 19. The drill stringcomponent as recited in claim 1, wherein the drill string componentcomprises a drill rod.
 20. The drill string component of claim 1,wherein at least a portion of the substantially cylindrical portion ofeach trough further comprises a plurality of longitudinally extendingridges that extend inwardly toward the central longitudinal axis. 21.The drill string component of claim 1, wherein the plurality of troughscomprise greater than 60% of the elongate length of the mid-bodyportion.
 22. The drill string component of claim 12, wherein the maleprojections of the single projecting portion are longitudinally spacedfrom the box and pin end portions by a separation distance that is lessthan about five feet.
 23. The drill string component of claim 13,wherein the male projections of sequential projecting portions arelongitudinally spaced from one another by a separation distance that isless than about five feet.